Smith number

A Smith number is a compositeinteger with the property that the sum of its digits is the same as the sum of the digits of its primefactors. For example, 16940 is Smith because 16940 = 2 x 2 x 5 x 7 x 11 x 11 and 1 + 6 + 9 + 4 + 0 = 2 + 2 + 5 + 7 + 1 + 1 + 1 + 1. The numbers are named after mathematician Albert Wilansky's brother-in-law, whose phone number is a Smith number.